Mass Air Flow Sensor, Checking: Notes

Special tools and workshop equipment required 

• multimeter.
• Wiring diagram.

Test requirements 

• The Mass Air Flow (MAF) Sensor -G70- fuse OK.
  Fig 1: Fuses On E-Box In Engine Compartment, Left Side

  Courtesy of AUDI OF AMERICA, LLC
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position "P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• Coolant Temperature at least 80° C.
• Ignition switched off.

Test procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK 

Start diagnosis 

-- Connect the scan tool.

-- Start engine and let it run at idle.

-- Using the scan tool, Check the air flow quantity of the Mass Air Flow (MAF) Sensor -G70- at idle:

Diagnostic text		Specified value
Air flow quantity at Mass Air Flow (MAF) sensor
Engine running at idle		2.00 to 5.00 g/sec

-- End diagnosis and switch ignition off.

If specified value is obtained, but DTC memory has a DTC concerning Mass Air Flow (MAF) Sensor -G70- :

-- Check voltage supply of Mass Air Flow (MAF) Sensor -G70- CHECKING VOLTAGE SUPPLY .

If specified value was not obtained:

-- Check the Mass Air Flow (MAF) Sensor -G70- electrical circuit CHECKING ELECTRICAL CIRCUIT .